Safety trocar assembly

ABSTRACT

A trocar assembly including a low-profile retractable shield deployable adjacent to a cutting element with a cross-sectional area which is small relative to the total cross-section of the assembly.

FIELD OF THE INVENTION

The present invention relates to medical equipment, in particular totrocar and similar devices used in surgical procedures and intended fortheir improvement.

BACKGROUND OF THE PRIOR ART

Trocars are used in medicine for making orifices and trocar portplacement in body cavity walls used further for diagnostic or surgicalinstrument insertion into body cavity. Trocar insertion into body cavitycan be accompanied with internal organ injury. To prevent such acomplication, the trocars are equipped with various protectors ofpiercing-cutting means. However, all known solutions do not eliminatethe problem of internal organ injuries.

The safety trocar penetrating instrument is known from the U.S. Pat. No.5,591,190, comprising port unit and trocar unit with obturator havingpiercing-cutting means. The device is equipped with protector forpiercing-cutting means made as a tubular shield situated betweenobturator and tubular cannula of port unit and movable relative toobturator from the extended position when it encloses piercing-cuttingmeans and prevents it from any contact, to the retracted one, whenpiercing-cutting means is open and can perforate the body cavity wall.Such a protector advances to the extended position when the resistanceof body cavity wall drops after the exposed piercing, cutting means hasalready entered the body cavity, i.e. after internal organs could haveready been injured.

Another trocar and cannula assembly are known from the U.S. Pat. No.5,246,425, wherein a tip protector comprises a plurality of projectionswhich, by the authors' idea should be displaced into an extendedposition before the piercing apex has been fully inserted into the bodycavity. However, such mechanism leads to inevitable injury of bodycavity wall, increased resistance to the device advance, the deviceadvance in jerks, and high probability of protector jamming. Moreover,when these members pass through fibrous anatomical structures:aponeuroses, fascias, muscles, the structure fibers enter either theprojections, or between the projections and tip. Further device advanceis possible solely by rupturing these fibers which, in its turn, resultsin increased tissue injury and in the device hindered advance.

The tissue fibers incorporated between projections and tip can jamprotector in the retracted position. In this case the jeopardy ofinternal body injury is even higher than by the performance of a trocarnon-equipped with protector, since a surgeon, being sure of the devicesafety, operates with less caution.

A trocar with a shield is disclosed by U.S. Pat. No. 5,797,943. Thegeometry of the descried shield should, by the authors' opinion, ensuresuccessive protection of various zones in piercing-cutting meanspractically simultaneously with their penetration to the body cavity.

However, shield members have such sizes, shape, arrangement and contactzone with body cavity wall that they generate considerable resistancebetween the shield and the body cavity wall tissues, and the latterholds the shield in totally retracted position, up to the shieldcomplete removal beyond the bounds of body cavity wall, which means thatno successive protection of piercing-cutting members takes place as theyenter the body cavity.

Similar demerit is found in U.S. Pat. Nos. 5,690,663, 5,709,671. Atrocar, having improved tip configuration is disclosed by U.S. Pat. No.5,709,671, where distal edge of tubular cannula is made sloping, tofacilitate the device passing through body cavity wall. In fact, thesurgeon has less difficulties in trocar passing through tissues sincesloping edge of cannula operates as a wedge giving the benefit of force,which facilitates tissue rupture by trocar passing. But tissue injuryduring the trocar performance remains considerable.

SUMMARY OF THE INVENTION

The invention objective is the decrease of internal organ injury riskupon trocar performance.

Another invention objective is increased reliability of protectoroperation by preventing jamming and engagement of body cavity walltissues between the members of trocar distal edge.

Another invention objective is decreased tissue injury of body cavitywall.

Another invention objective is facilitated trocar passing through bodycavity wall.

Another invention objective is decreased material consumption for thedevice, design simplification and device low-cost manufacturing.

Another invention objective is independent of each other operation startand finish of cutting members dependable on tissue local biomechanicalproperties.

Another invention objective is accurate adaptation of orifice sizes inbody cavity wall to the cannula diameter.

The above noted objectives are accomplished by a safety trocar assemblyhaving a portal unit with elongated obturator removably inserted throughthe cannula and having a handle on its proximal end and a penetratingend on its distal end. The penetrating end is exposed through thecannula open distal end and has a cutting means, a penetrating apex, anda sloping side wall immovable relative to obturator. The obturator isprovided with a protector mean as having a bias means and a movablepenetrating apex shield that in its retracted position opens thepenetrating apex and in its extended position closes the penetratingapex preventing it from any contact with patient's organs. In theprojection onto transverse plane, the obturator sloping side wallsurrounds the penetrating apex shield. It means that the penetratingand, consequently, also the penetrating apex shield have little crosssection dimensions in comparison with the obturator. This allowsreduction of the resistance of body tissue during penetrating apexshield displacement to its extended position and provides fast actingprotection of the penetrating apex immediately after the penetration ofpenetrating apex distal end into the body cavity, however, before thepenetrating end has been fully inserted. Further dilation of the orificein the body wall is carried out by cutting means located on the slopingside wall. The penetrating apex shield is made tubular of circular orflattened cross section, totally closed or having a slot on one side.The distal edge of this shield forms a fence precluding theintroduction, jamming; and engagement of tissue fibers of the bodycavity wall between the penetrating apex shield and the penetrating apexas well as between the penetrating apex shield segments. As a result,the injury of body cavity wall is decreased and trocar passing throughbody cavity wall is facilitated.

The shield for protection of the cutting means is characterized by alocal comparative height equal to the ratio of local maximal shieldheight to a local maximal shield width measured in the same localobturator transverse plane. This parameter characterizes such propertiesof the protector sheild as the resistance of body tissue to shielddisplacement to is extended (protected) position and velocity of thisdisplacement. The less the value of this parameter the less the tissueresistance and the faster the shield displacement to extended position.According to the present invention, the shield, particularly madeplate-shaped, has maximal value of the local comparative height lessthan 0.5. This shield is a low profile shield and the perimeter of itscross section insignificantly exceeds the perimeter of tissue incisionmade by the cutting means. Moreoever, the height of this plate-shapedshield (the plate thickness) amounts 0.4 to 2 mm for obturator withouter diameter 10 to 12.5 mm and 0.4 to 1.2 mm for obturator with outerdiameter 5 to 6.5 mm. This shield is a fast acting protector enteringthe tissue incision without substantial resistance of tissue incisionedges and enabling the shield entry the body cavity immediately afterentry there the cutting means. As a result, the risk of patient internalorgan injury is significantly decreased.

In version embodiment, a safety trocar assembly comprises a penetratingmeans with at least two penetrating zones and a protector means withindependent protector memebers, made as shields, for independentprotection of each of said penetrating zones, and a resilient bias meansfor each of the protector members. This protects the penetrating zone(knife) which enters the body cavity independently of anotherpenetrating zones (knives) which have not yet entered the body cavityand continue to cut the tissue. In version embodiment, there are distaland proximal penetrating zones provided with a distal and a proximalindependent shield, respectively. The distal penetrating zone is thefirst one that enters the body cavity and is a main cause of internalorgan injury, so its independent and fast protection eliminates trocarprocedure complications.

In version embodiment, the displacement of the proximal shield from theextended position to the retracted position demands greater force thanidentical displacement of the distal shield. That can be achieved bylarger rigidity of the bias means (in the form of a spring) of theproximal shield than one of the distal shield. As a result, the proximalpenetrating zone forms such final dimensions of orifice that isaccurately adapted to the cannula outer diameter. Described penetratingand protector means have so simple a design (for example, makingprotector and biasing members as a one detail) so as to permit theirarrangement in the limits of obturator distal part. Such implementationincreases trocar reliability and reduces its manufacturing cost.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments of the safety trocar assembly of the subjectapplication will be described below with reference to the followingdrawings wherein:

FIG. 1 is a perspective view of trocar assembly with tubular penetratingapex shield.

FIG. 2 is a longitudinal section of trocar assembly of the FIG. 1.

FIG. 3 is a perspective view of trocar assembly with spring penetratingapex shield.

FIG. 4 is a perspective view of distal part of trocar assembly of theFIG. 3.

FIG. 5 is a longitudinal section of trocar assembly of the FIG. 4 anddemonstrates penetrated apex shield in extended position.

FIG. 6 is a longitudinal section of trocar assembly of the FIG. 4 anddemonstrates penetrated apex shield in retracted position.

FIG. 7 is a perspective view of trocar assembly with groove penetratingapex shield.

FIG. 8 is a longitudinal section of distal part of trocar assembly ofthe FIG. 7 with groove shield in extended position.

FIGS. 9-11 are sections of trocar assembly of the FIG. 8 on the levels9—9, 10—10, 11—11, respectively.

FIG. 12 is a longitudinal section of distal part of trocar assembly andgroove shield of the FIG. 8.

FIG. 13 is a longitudinal section of distal part of trocar assembly ofthe FIG. 7 with groove shield in retracted position.

FIG. 14 is a longitudinal section of distal part of trocar assembly andgroove shield of the FIG. 13.

FIG. 15 is a perspective view of trocar assembly with two independenttubular shields.

FIG. 16 is a left-hand view of device of the FIG. 15.

FIG. 17 is a longitudinal section of device of the FIG. 15.

FIG. 18 is a longitudinal view of trocar unit of device of the FIG. 17.

FIG. 19 is a perspective view of the trocar unit of the FIG. 18.

FIGS. 20-25 demonstrate successive changes in mutual positions of theshields at the stages of trocar penetrating end passing though bodycavity wall.

FIG. 26 is a perspective view of trocar assembly with low profileprotector.

FIG. 27 is a knife-side view of distal part of trocar assembly of theFIG. 26.

FIG. 28 is a left-hand view of the trocar assembly of FIG. 26.

FIG. 29 is a protector-side view of distal part of trocar assembly ofthe FIG. 26.

FIG. 30 is a longitudinal section of distal part trocar assembly of theFIG. 29.

FIG. 31 is a longitudinal section of the distal part of trocar assemblyof the FIG. 29 with protector displaced to retracted position.

FIG. 32 is a perspective view of trocar assembly with low profileinverted shield.

FIG. 33 is left-hand view of device of the FIG. 32.

FIG. 34 is a top view of distal part of device of the FIG. 32.

FIG. 35 is a knife-side view of distal part of device of the FIG. 32.

FIG. 36 is a shield-side view of distal part of device of the FIG. 32.

FIG. 37 is a longitudinal view of device of the FIG. 32.

FIG. 38 is a view of trocar unit of device of the FIG. 32.

FIG. 39 is a longitudinal section of distal part of device of the FIG.32 with shield in extended position.

FIG. 40 is a longitudinal section of distal part of device of the FIG.32 with shield between extended and retracted positions.

FIG. 41 is a longitudinal section of distal part of device of the FIG.32 with shield in retracted position.

FIG. 42 is a perspective view of trocar assembly with two independentlow profile inverted shields.

FIG. 43 is a left-hand view of device of the FIG. 42.

FIG. 44 is an enlarged distal part of device of the FIG. 42.

FIG. 45 is a longitudinal section of distal part of device of the FIG.42.

FIG. 46 is a distal part of device of the FIG. 42 with shields betweenextended and retracted positions.

FIG. 47 is a longitudinal section of device of the FIG. 46.

FIG. 48 is a distal part of the device of the FIG. 42 with shield inretracted position.

FIG. 49 is a longitudinal section of device of the FIG. 48.

FIG. 50 is a perspective view of safety trocar with three independentshields.

FIGS. 51, 52 are views of distal part of device of the FIG. 50 fromknife- and shield-side, respectively.

FIG. 53 is a longitudinal section view of distal part device of the FIG.50.

FIG. 54 is a longitudinal section view of distal part device of the FIG.50 with plated shield in retracted position.

FIGS. 55-63 demonstrates positions of shields at various penetrationstages of the distal part of FIG. 50 device through body cavity wall.

FIG. 64 is a perspective view of trocar assembly, wherein proximal biasmembers of lateral shields are made more rigid than distal ones.

FIG. 65 is a knife-side view of distal part of device of the FIG. 64.

FIG. 66 is a shield-side view of distal part device of the FIG. 64.

FIG. 67 is a longitudinal section view of device of the FIG. 66.

FIG. 68 is a longitudinal section view of device of the FIG. 66 withplated shield in retracted position.

FIG. 69 is a perspective view of trocar assembly with low profileinverted stepwise shield.

FIGS. 70-72 demonstrate the displacement stages of shield of device ofthe FIG. 69 from extended to retracted position.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Safety trocar assembly is intended for making orifices in body cavitywall and generation of conditions for subsequent introduction ofinstruments into a body cavity.

Before addressing specific implementations of the present invention indetail, it should be noted that the invention will be presented withreference to numerous examples, each of which illustrates one or morepreferred feature of the invention. These various preferred features mayeach be used individually to advantage with an otherwise conventionaltrocar. In most preferred implementations, however, multiple preferredfeatures are combined to provide a trocar with greatly enhanced levelsof safety to the patient and/or professional staff, and/or to providenumerous other advantages as will become clear from the followingdescription.

Turning now to the Figures, FIGS. 1 and 2 illustrate a first embodimentof a trocar assembly 1 in which a retractable shield 14 is deployed toselectively shield only the distal portion of a penetrating end 10. As aresult, the shield extends itself as soon as the distal portion clearsthe tissue wall, well before fill penetration of end 10 occurs.

More specifically, FIG. 1 shows trocar assembly 1, comprising trocarunit 2 and portal unit 3. FIG. 2 shows a longitudinal section of trocarassembly 1 in enlarged scale. Portal unit 3 has tubular cannula 4,portal housing 5 and inner seals 6, 7 located in portal housing 5 andaimed to maintain insulation of the body cavity. Tubular cannula 4 hasan open distal end 8. Trocar unit 2 has elongated obturator 9 adapted tobe removably inserted through cannula 4 and having a penetrating end 10exposed through cannula 4 open distal end 8. Penetrating end 10 haspenetrating apex 11 and a sloping side wall 12. Longitudinal opening 17of obturator 9 houses protector means 13 comprising tubular penetratingapex shield 14 adapted to actuate between a retracted position and anextended position (shown in FIG. 2), when shield 14 surroundspenetrating apse 11, and sloping side wall 12 surrounds shield 14 fromthe outside. Distal edge 15 of shield 14 forms uninterrupted hedge.Protector means 13 comprises bias means made as a compression spring 16.In the embodiment shown in FIGS. 1, 2 penetrating apex 11 formed bypointed distal edge of cylindrical piece 18, having circular ledge 19which is abutted by circular ledge 20 of penetrating apex shield 14,when shield 14 reaches its extended position. Stopper bushing 21 abuttedby spring 16 is tightly placed on proximal end of cylindrical piece 18.

Device 1 is operated as follows:

Surgeon holds device 1 by housing 5 and push member 22 situated onobturator 9 proximal end. Device 1 is oriented approximatelyperpendicular to body cavity wall and is pressed to it, applying pushingeffort to push member 22. The resistance force of pierced tissuesapplied to shield distal edge 15, displaces shield 14 towards retractedposition so that penetrating apex 11 strips bare and pierces body cavitywall tissues. In this process, shield uninterrupted distal edge 15 formsa hedge precluding the introduction and engagement of tissue fibers ofbody cavity wall between shield 14 and penetrating apex 11, thusensuring smooth motion of device 1 through the tissues. When penetratingapex 11 and shield distal edge 15 have entered a patient's body cavity,however, before penetrating end 10 has been fully inserted the forceapplied to shield distal edge 15 is removed, and spring 16 returnsshield 14 to extended protected position, and further movement ofpenetrating end 10 to body cavity occurs with protected penetrating apex11, which precludes the injury of inner organs. Penetrating apex 11 canhave diversified shapes, for instance, conical or pyramidal one, withcutting edges (not shown in the Fig.).

Turning now to FIGS. 3-6, these illustrate a variant of the embodimentof FIGS. 1 and 2 in which the shield is implemented as a helical coil ofresilient wire formed with a closed portion 114 acting as the shield anda spring portion 116 which provides forward biasing. In other respects(preferred dimensions etc.), this implementation is similar to theprevious embodiment. More specifically, FIG. 3 shows safety trocarassembly 101, comprising trocar unit 102 and portal unit 103.

FIG. 4 shows distal part 123 of device 101 in enlarged scale, and FIG. 5shows a longitudinal section of distal part 123. Penetrating end 110,protruding through cannula 104 open distal end 108, has penetrating apex111 made integral with obturator 109, per ng apex shield 114, and biasmeans made as a compression spring 116. In this, shield 114 and spring116 are made as a single piece from coiled springy rod fixed inobturator 109 circular groove 124. Penetrating end 110 also has slopingside wall 112, whereon outer cutting means 125, 126 made as outercutting members are located, and which can be made of the same materialas obturator 109.

FIGS. 4, 5 show shield 114 in extended protected position.

FIG. 6 shows shield 114 in retracted position

Trocar assembly 101 operates similarly to trocar assembly 1.

Turning now to FIGS. 7-14, these illustrate a similar concept as appliedto a penetrating end formed as a flat knife. Specifically in relation toconfigurations employing cutting edges provided by flat blades, it ispreferred that the shield element(s) are formed as low-profile shieldsin a manner that they experience very low resistance to returning totheir distal protective positions almost immediately that the cuttingedge clears the tissue wall.

In order to better define the preferred geometrical features whichensure this rapid return of the shield to its operative position,reference will be made in the description and claims to variousterminology which is defined as follows:

-   -   the “displacement vector” of a shield is the direction defining        its retraction between its extended and retracted positions.        This direction generally lies in a plane parallel to the        longitudinal axis of the trocar assembly,    -   the “cutting plane” is a plane defined by a cutting edge of the        flat blade and the central longitudinal axis of the device;    -   the “shield height” is the distance between the cutting plane        and the outer surface of the shield as measured perpendicular to        said cutting plane;    -   the “shield width” is the maximal distance between the        longitudinal axis of the device and the outer surface of the        shield;    -   the “local comparative height” of the shield is the ratio of        local maximal height of the shield to the local maximal width of        the shield measured in a common plane perpendicular to the        device longitudinal axis;    -   the “proximal protected position” of the shield is the extreme        proximal position of the shield which offers complete protection        of the cutting edge; and    -   the “screen area” of the shield is the section of the shield        which, when the shield is located in the proximal protected        position, is situated between two planes perpendicular to the        device longitudinal axis so that one of the planes intersects        the proximal end of the cutting edge, whereas the other the        plane intersects distal end of the cutting edge, and the plane        equidistant from both the perpendicular planes divides the        screen area into proximal and distal screen zone.

In the case of a shield located on both sides of a flat blade such as isshown here, reference is also made to a “full local comparative height”of the shield defined as the ratio of total local maximal height of theshield and the local maximal width, wherein the total local maximalheight of the shield is the distance between outer surfaces of oppositeparts of the shield measured perpendicular to the cutting plane.

According to these definitions, in the case of a two-sided shield, it isparticularly preferred that the full comparative height of the shieldalong the proximal screen area is below 1.4.

Turning now to the structural details of this embodiment, FIG. 7 shows asafety trocar assembly 201, comprising trocar unit 202 and portal unit203.

FIG. 8 shows longitudinal section of obturator 209 distal part 227 inenlarged scale. Obturator distal part 227 comprises penetrating apex 211with penetrating apex cutting means looking like distal knife 228 andouter cutting member looking like proximal knife 225. Both knives—228,225—are made on the plate-shaped base 229, which has two springy arms230, 231 with ledges 232, 233 in its proximal section, said ledgesensuring engagement of plated base 229 and obturator 209. Penetratingapex shield 214 is made as two-sided low profile shield and haslongitudinal slot 234 plate base 229 passes through. Bias means is madeas a compression spring 216, which abuts shield 214 with its distal face235, whereas its proximal one abuts plate-shaped base 229. In FIGS. 7,8, 12 shield 214 is in extended position so that its further distaldisplacement is limited by ledge 219 on plate-shaped base 229, which isabutted by shield 214 ledge 220. In FIGS. 13, 14 shield 214 is in actedposition.

Device 201 operates similarly to device 1.

Turning now to FIGS. 15-25; these illustrate a particularly preferredembodiment which combines a distal-portion shield of the typeillustrated in FIGS. 1 and 2 with a locking mechanism.

In a further preferred feature, which may be used either alone or incombination with the locking mechanism, the distal-portion shield iscombined with a conventional large-diameter shield, in this case formedas concentric cylinders, to provide two-stage protection. Thedistal-portion shield provides immediate protection as soon as thedistal portion of the penetrating end clears the tissue wall (FIG. 23),while the large-diameter shield provides additional protection once thepenetrating end is fully inserted (FIG. 25). In the most preferredimplementation shown here, the locking mechanism is operative to lockboth shields when the obturator is removed. More specifically, FIG. 15shows safety trocar assembly 401 with mutually independent shields 414,436. Device 401 comprises trocar unit 402 and portal unit 403. Portalunit has tubular cannula 404 and portal housing 405.

FIG. 16 shows a left-hand view of device 401.

FIG. 17 shows a longitudinal section view of device 401.

Trocar unit 402 has obturator 409 comprising distal part 427 andproximal part 438. Penetrating end 410 comprising penetrating apex 411,sloping side wall 412 and outer cutting members 425, 426 450 withcutting edges 451 protruding above the sloping side wall 412 level.There are two tubular shields: penetrating apex shield 414 and outershield 436. There are two independent, separate for both shields 414 and436 bias means made as compression springs 416, 451. There is common forboth shields 416, 436 lock means 435 comprising obturator-situatedcontrolling member 440, partially protruding laterally of obturatordistal part 427, and adapted to the interaction with inner surface 441of tubular cannula 404. Controlling member is made integral withabutting member 442, having outer abutting surface 443 and innerabutting surface 452. Abutting member 442 by springy legs 444, 445 isspring-loaded to obturator 409.

FIG. 18 shows a longitudinal section of trocar unit 402 of device 401.

FIG. 19 shows top view of trocar unit 402.

In FIGS. 18, 19 lock means 435 is in lock position and locks shields 414and 436 in protected position. Shield 436 wall has through elongatedslot 446 with two different-width sections—distal section 447 isnarrower than proximal section 448. Controlling member 440 has widthless than that of slot 447 distal section, whereas abutting member 442is wider than distal section 447 but narrower than slot 448 proximalsection.

When trocar unit 402 is outside portal unit 403 (FIGS. 18, 19), legs444, 445 shift abutting member 442 to the lock position, when abuttingmember 442 partially enters slot 446 proximal section 448, and outerabutting surface 443 is set opposite of ledge 449 on outer shield 436,precluding shield 436 distal displacement, and inner abutting surface452 is set opposite of proximal face 453 of penetrating apex shield 414,also precluding shield 414 proximal displacement. Unlocking of bothshields 414, 436 occurs with trocar unit 402 entering portal unit 403,which takes place when controlling member 440 interacts with cannula404, and thus forces abutting member 442 out of interaction zone withshields 414, 436.

FIGS. 20-25 show operating shields on successive stages of penetratingend 410 passing through body cavity wall 454.

FIG. 20 shows staring moment of trocar assembly 401 interaction withbody cavity walk when outer shield 436 is between its extended andretracted positions, penetrating apex shield 414 is in retractedposition, and penetrating apex 411 has incorporated into body cavitywall 454.

FIG. 21 shows the moment when both shields 414, 436 are forced out bybody cavity wall tissue to retracted position.

FIG. 22 shows the moment when both shields 414, 436 are in retractedposition, and penetrating apex 411 has penetrated into body cavity.

FIG. 23 shows the moment immediately after the displacement ofpenetrating apex shield 414 to extended protected position. In thisprocess, outer cutting members 426, 426, 450 continue cutting tissue.

FIG. 24 shows the moment before shield 436 operation.

FIG. 25 shows both shields 414, 436 in extended position.

As can be seen, independent performance of shields 414 and 436 greatlyensures trocar safe operation.

Turning now to FIGS. 26-31, these show a further embodiment of thepresent invention as applied to an obturator 509 with a distal knife528. In this case, a one-sided low profile shield 514 is used. Since thecross-sectional area of the shield adds relatively little to thecross-sectional area of the knife itself, the shield advances throughthe incision to its distal position to provide protection almostimmediately on penetration of the tissue wall. Preferably, according tothe terminology defined above, the shield local comparative height alongthe proximal screen area for a one-sided shield is below 0.8.

FIG. 26 shows safety trocar assembly 501 with one-sided low profileshield 514. Device 501 has trocar unit 502 and portal unit 503. Portalunit 503 has cannula 504 and portal housing 505.

FIG. 27 shows the view of device distal part 523 from the side ofpenetrating apex cutting means made as distal knife 528.

FIG. 28 shows left-hand view of device 501.

FIG. 29 shows device distal part 523 from the side of shield 514.

FIG. 30 shows longitudinal section of device distal part 523 when shield514 is in extended position.

Trocar unit 502 has obturator 509 with penetrating end 510 with slopingside wall 512 and outer cutting members 525, 526 so that outer cuttingmembers 525, 526 are made integral with obturator 509. Indented distalknife 528 is made on plate-shaped base 529, and has one-sided lowprofile shield 514 with bias means made as compression spring 516.

When penetrating end 510 passes through body cavity wall, the tissueresistance force shifts shield 514 to retracted position (FIG. 31), andstripped knife 528 makes an orifice in the tissue. Low profileprotectors, both one-sided, and two-sided—are the protectors againstinstantaneous operation, i.e. they operate upon knife minimalpenetration to body cavity.

FIGS. 32-41 show a further embodiment with shields for the lateralblades. Advantageously, the shield may be formed in such a manner as toprovide protection for the distal portion of the blade while theproximal portion is still operative, thereby providing enhancedprotection.

FIG. 32 shows safety trocar assembly 701 with one-sided low profileinverted shield 736. Device 701 has trocar unit 702 and portal unit 703.Portal unit 703 has cannula 704 and portal housing 705. Trocar unit hasobturator 709 (FIG. 34—top view of device 701 distal part 723) withpenetrating end 710. Penetrating end 710 comprises blunt apex 755,sloping side wall 712, two knives 725, 725 and inverted shield 736.

FIG. 35 shows device distal part 723 from the side of knives 725, 726,

FIG. 36 shows device distal part 723 from the side of shield 736.

FIG. 37 shows longitudinal section of device 701.

FIG. 38 shows longitudinal section of device 701 trocar unit 702. Trocarassembly 701 has lock means 735 for shield 736. Lock means 735 hasobturator-situated controlling member 740, partially protrudinglaterally of obturator 709 and adapted to the interaction with inner740, 741 of cannula 704. Controlling member 740 is made integral withabutting member 742, having abutting surface 743. Abutting member 742 isspring-loaded to obturator 709 by springy legs 744, 745. Shield 736 hasabutting bar 758. When trocar unit 702 (FIG. 38) is outside the portalunit 703, legs 744, 745 shift abutting surface 743 to the level ofabutting bar 758, and such mutual disposition of shield 736 and lockmeans 735 is the lock position which prevents shield 736 proximaldisplacements

Unlocking of shield 736 takes place when trocar unit 702 is introducedto portal unit 703 but only after protected penetrated end 710 passesthrough distal inner seals 706, 707 so that controlling member 740,being resisted by cannula 704 inner surface 741, shifts abutting member742 from the interaction zone with abutting bar 758.

FIGS. 39, 40, 41 show longitudinal section of device 701 distal part 723in enlarged scale at shield 736 various performance stages.

FIG. 39 shows shield 736 in extended position. Shield 736 is made platedand besides abutting bar 758 has protection edges 759, 760, guidingslots 761, 762, through which cotters 763, 764 are passing, window 765,wherein bias compression spring 716 is mounted, whose distal end abutsshield 73, whereas proximal end 766 is fixed to plate-shaped base 729 ofknives 725, 726. Shield 736 is an inverted shield which means that whenit shifts from extended position to retracted position, the opening ofknives 725, 725 starts from their proximal sections 767, 768. Thisoperation mechanism of shield 736 is achieved owing to the fact thatrelative to the device longitudinal axis the incidence angle of the lineconnecting distal point 769 and proximal point 770 on protection edge759 is more acute than the incidence angle of the line connecting distaland proximal points 771, 772 on knife 725.

FIG. 41 shows shield 736 in retracted position. Consequently, aspenetrating end 710 enters body cavity, closing of knives 725, 726starts from their distal sections which ensures low injury level.

The embodiment of FIGS. 42-49 generally parallels the embodiment ofFIGS. 32-41, but provides independently operative shields for thelateral blades. Thus, FIG. 42 shows a safety trocar assembly 801 withtwo independent low profile inverted shields 836, 871. Device 801comprises trocar unit 802 and portal unit 803. Portal unit 803 comprisescannula 804 and housing 805.

FIG. 43 shows left-hand view of device 801 in enlarged scale.

FIG. 44 shows device 801 distal part 823 in enlarged scale. Trocar unit802 comprises obturator 809 with pen ting end 810 which is formed byblunt apex 855, sloping side wall 812, with protection edges 859, 860 ofshields 836, 871, and knives 825, 826 protruding above it. Shields 836,871 are made plated and equipped with independent bias compressionsprings 816, 851. Knives 825, 826 (FIG. 49) are made on plate-shapedbases 829, 872.

FIGS. 45-59 show mutual arrangement of knives 825, 826 and shields 836,871 at various operation stages of shields 836, 871. FIG. 45 shows bothshields 836, 871 in extended-protected position. FIGS. 46, 47 showshields 836, 871 in intermediate position between extended and retractedposition, when only proximal sections 867, 868 of knives 825, 826 areopen. FIGS. 48, 49 show shields 836, 871 in retracted position, whenboth knives 825, 826 are open along their entire lengths.

FIGS. 45-49 show symmetrical operation of shields 836, 871, but inasmuchas shields 836, 871 are made independent and are equipped withindependent bias springs 816, 851, so the operation of shields 836, 871can be independent, non-simultaneous (not shown on Figs.). The operationnon-simultaneity stems from resistance non-simultaneity of tissueelements of body cavity wall. That is the concept of independent shieldspermits to take into account and to respond automatically to localproperties of tissues.

However, for the surgeon the mode of device 801 operation does notdiffer from that of similar alternative devices.

FIGS. 50-63 illustrate an alternative type of shield for lateral blades,in this case combined with a distal knife and shield similar to those ofFIGS. 26-31. The lateral shields are here implemented as resilientelements which react substantially independently to force applied neartheir distal and proximal ends. As a result, this configuration alsoprovides protection for the distal portion of the blades while theproximal portion is still operative (FIGS. 61 and 62). FIG. 50 showsperspective view of safety trocar assembly 901 comprising trocar unit902 and portal unit 903. Portal unit 903 has cannula 904 and housing905. Trocar unit has obturator 909 with penetrating end 910. Penetratingend is formed by sloping side wall 912, penetrating means 973 fororifice formation in body cavity wall, and protector means 913 for saidpenetrating means 973. Penetrating means 973 comprises penetrating zonesformed by knives 928, 925, 967, 926, 968 made on common plate-sided base929 (FIG. 53) so that knives 925 and 967, as well as knives 926 and 968have cutting edges confluent with one to another. Each penetrating zonehas protector member, and each protector member has its own bias member.For penetrating zone 928 made as indented knife, protector member ismade as plane-shaped shield 914, whereas bias member as compressionspring 916.

Protector members 969 and 970 of knives 925, 967 have bias means 951,979, respectively, so that protector members 969, 970 are made as acommon shield 936. Common shield 936 and bias means 951, 979 are made asa single resilient part, having a slat 980, which in extended position(FIGS. 51, 52, 53) is situated parallel to cutting edge of knives 925,967, and bias means 951, 979 made as resilient elements, each of thembeing connected to slat 980 by one its end 981, 982, whereas the otherone 983, 984 is connected to the plate-shaped base 929. Protectormembers 985 and 986 of knives 926 and 968 have bias means 987, 988,respectively, so that protector members 985, 986 are made as a singleresilient part, having a slat 990 which in extended position is situatedparallel to cutting edges of knives 926, 968, and

bias means 987, 988 are made as resilient elements, each of them beingconnected to slat 980 by one its end 991, 992, whereas the other ones993, 994 are connected to the plate-shaped base 929.

FIGS. 55-63 show mutual arrangement of protector members at variousstages of penetrating end 910 passing through body cavity wall 954.

FIG. 55 shows shields 914, 936, 989 in extended position.

FIG. 56 shows shield 914 in retracted position, and open knife 928creates an orifice in body tissue.

FIG. 57 shows protector members 969, 985 displaced to retractedposition, and knives 925, 926 create orifice in body tissue.,

FIG. 58 shows all shields 914, 936, 989 in retracted positions.

FIG. 59 shows knife 928 entry to body cavity.

FIG. 60 shows the point immediately after shield 914 displacement toextended protected position.

FIG. 61 shows knives 925 and 926 entry to body cavity, one of them 925being shown protected by protector member 969, which displaysindependent operation of symmetrical protector members 969 and 985, thusensuring maximal fast operation of protector members, and, consequently,minimal injury of internal organs.

FIG. 62 shows protector members 914, 969, 985 in extended-protectedposition.

FIG. 63 shows penetrating end 910 as totally entering the body cavity,with totally protected penetrating means.

FIGS. 64-68 show an embodiment generally similar to that of FIGS. 50-53,but wherein the resilient elements are formed with greater springresistance at their rear proximal end than at their distal end, therebyalso tending to preclude over-widening of the incision.

FIG. 64 shows a safety trocar assembly 2001 comprising trocar unit 2002and portal unit 2003. Portal unit 2003 has cannula 2004 and housing2005. Trocar unit has obturator 2009 with penetrating end 2010.Penetrating end is formed by sloping side wall 2012, penetrating means2073 for orifice formation in body cavity wall, and protector means 2013for said penetrating means 2073. Penetrating means 2073 comprisespenetrating zones formed by knives 2028, 2025, 2067, 2026, 2068 made oncommon plate-sided base 2029 (FIGS. 65, 67) so that knives 2025 and2067, as well as knives 2026 and 2068 have cutting edges confluent intoeach other. Each penetrating zone has protector member, and eachprotector member has its own bias member. For penetrating zone 2028 madeas indented knife, protector member is made as plate-shaped shield 2014,and bias member is made as compression spring 2016.

Protector members 2069 and 2070 of knives 2025, 2067 have bias means2056, 2079, respectively, so that protector members 2069, 2070 as madeas a common shield 2036. Common shield 2036 and bias means 2051, 2079are made as a single resilient part, having a slat 2080, which inextended position (FIGS. 64, 65) is situated parallel to cutting edgesof knives 2025, 2067, and bias means 2051, 2079 are made as resilientelements, each of them being connected to slat 2080 by one its end 2081,2082, whereas the other one 2083, 2084 is connected to the plate-shapedbase 2029. Protector members 2085 and 2086 of knives 2026 and 2068 havebias means 2087, 2088, respectively, so that protector members 2085,2086 are made as a common shield 2089. Common shield 2089 and bias means2087, 2088 are made as a single resilient part, having a slat 2090,which in extended position is situated parallel to cutting edges ofknives 2026, 2068, and bias means 2087, 2088 are made as resilientelements, each of them being connected to slat 2090 by one its end 2091,2092, whereas the other ones 2093, 2094 are connected to theplate-shaped base 2029. In this, proximal bias means 2079 is made morerigid than distal bias means 2051, consequently, the displacement ofproximal protector member 2070 and knife 2067 opening, and further on,tissue cutting at this level of penetrating means occurs at highertissue tension than by tissue cutting at the level of knife 2025.

Shield 2089 operates in similar manner.

Such tissue cutting mechanism precludes generation of excessive diameterorifice in body cavity wall.

FIGS. 65-72 show an embodiment generally similar to that of FIGS. 32-41,in which the shield is formed with a stepped edge. The inclination ofthe steps to the longitudinal axis of the assembly varies from greatestat the distal part of the shield to least at the proximal part of theshield. This tends to ensure that less force is required to causeretraction of the shield at smaller diameters of hole than at largediameters, thereby limiting over-widening of the incision. Thus, FIG. 82shows safety trocar assembly 3001 with low profile inverted shield 3036.Device 3001 has trocar assembly 3002 and portal assembly 3003. Portalassembly 3003 has cannula 3004, and housing 3005. Trocar assembly hasobturator 3009 with penetrating end 3010 formed by blunt apex 3055, andsloping side wall 3012, with protector edges 3059, 3060 of shield 3036and knives 3025, 3026 protruding over it.

Trocar assembly 3001 has lock means 3035 for shield 3036. Lock means3035 has obturator-situated controlling member 3040, partiallyprotruding laterally of obturator 3009, and adapted to the interactionwith inner surface 3041 of cannula 3004. Controlling member 3040 is madeintegral with cutting member 3042, having abutting surface 3043.Abutting member 3042 by springy legs 3044, 3045 is spring-loaded toobturator 3009. Shield 3036 has abutting bar 3058. When trocar unit 3002is outside portal unit 3003, legs 3044, 3045 shift abutting surface 3043to the level of abutting bar 3058, and such mutual arrangement of shield3036 and lock means 3035 is the lock position (not shown in the Fig.),wherefrom shield 3036 proximal displacement is impossible.

FIGS. 70, 71, 72 show longitudinal section of device 3001 distal part3023 in enlarged scale at various stages of shield 3036 operation

FIG. 70 shows shield 3036 in extended position. Shield 3036 is madeplated and has, in addition to abutting bar 3058 and protection edges3059, 3060, guiding slots 3061, 3062, through which cotters 3063, 3064are passing, window 3065, wherein bias compression spring 3016 ismounted, abutting shield 3036 by its distal end, and fixed toplate-shaped base 3029 by its proximal end.

FIG. 70 shows shield 3036 in the position intermediate between extendedand retracted ones.

FIG. 71 shows shield in retracted position.

Protector edges 3059, 3060 are made stepwise with varying slope of steps3095 so that in distal-proximal direction the slope of steps 3095relative to device 3001 longitudinal axis decreases, and, consequently,in the same direction decreases the force of steps 3095 engagement withthe tissue, hence, larger tension is required for shield 3036 proximaldisplacement upon tissue interaction with proximal steps than it is fortissue interaction with distal steps, and hence, cutting of tissue atthe level of distal sections 3025, 3026 occurs with smaller tissuetension than at the level of proximal sections of knives 3025, 3026.Such tissue cutting mechanism precludes generation of excessive diameterorifice in body cavity wall.

Although the present invention has been shown and described in terms ofpreferred embodiments, it will be appreciated that various changes andother modifications are contemplated within the spirit and scope of thepresent invention as defined by the following

1. A safety trocar assembly having: a longitudinal central axis; aportal unit with elongated, tubular cannula having an open distal end; atrocar unit having an elongated obturator adapted to be removablyinserted through said cannula, having a handle on a proximal end, and apenetrating end on a distal end, said penetrating end exposed throughsaid open distal end of said cannula and having a cutting means formaking an orifice in body cavity wall, a penetrating apex, and a slopingside wall that are immovable relative to said obturator; a protectormeans situated on said obturator and having a penetrating apex shieldadapted to actuate between a retracted position in which saidpenetrating apex is open and an extended position in which saidpenetrating apex is closed by said penetrating apex shield and in theprojection onto the plane normal to said longitudinal axis said slopingside wall surrounds said penetrating apex shield; said penetrating apexshield surrounds said penetrating apex and has distal edge forming meansfor precluding the introduction, jamming, and engagement of tissuefibers of body cavity wall between said penetrating apex shield and saidpenetrating apex; bias means for biasing said penetrating apex shieldtoward said extended position and for permitting said penetrating apexshield move to said retracted position in response to a proximallydirected force applied to said penetrating apex shield distal edge; saidbias means returning said penetrating apex shield to said extendedposition when the force applied to said penetrating apex shield distaledge is removed, that occurs when said penetrating apex and saidpenetrating apex shield distal edge have entered a patient's bodycavity, however, before said penetrating end has been fully insertedinto body cavity.
 2. Device according to claim 1, wherein said biasmeans is made as a spring mounted between said penetrating apex shieldand parts of said obturator.
 3. Device according to claim 2, whereinsaid spring is situated in said obturator distal part.
 4. Deviceaccording to claim 1, wherein said penetrating apex shield is tubular.5. Device according to claim 1, wherein: a displacement of saidprotector between its said extended and retracted positions is in theplane parallel to said longitudinal central axis; said cutting meanscomprises at least on cutting edge having distal end and situated in theplane parallel to said longitudinal central axis so that this plane isthe cutting plane of said cutting edge; said protector means has ashield for protection of said cutting edge; said shield has a protectedposition wherein said cutting edge distal end is protected; said shieldhas a screen area portion of the outer surface of said shield which,when said shield is in said protected position, is located outside saidtubular cannula and outside said sloping side wall presenting an openpart of said shield in said protected position; said shield has a shieldheight and as such saves the distance from said shield outer surface tosaid cutting plane; said shield has a shield width and as such servesthe distance from said shield out surface to said longitudinal centralaxis; said shield is characterized by a local comparative height equalto the ratio of the local maximal of said shield height to the localmaximal of said shield width measured in their common local planeperpendicular to said device longitudinal axis; said shield islow-profile having maximal said local comparative height that within thelimits of said screen area is less than 0.5.
 6. Device according toclaim 5, wherein said penetrating apex is plate-shaped and saidpenetrating apex shield made as said low profile shield.
 7. Deviceaccording to claim 5, wherein said cutting means has an outer cuttingmeans having at least one outer cutting member made as a knife situatedoutside of said penetrating apex shield within the limits of saidsloping side wall.
 8. Device according to claim 7, wherein there is atleast one outer shield for protecting said outer cutting means,therewith said penetrating apex shield and outer shield are movableindependently of one another.
 9. Device according to claim 8, whereinsaid outer shield is tubular and surrounds said penetrating apex,penetrating apex shield, and outer cutting means in said outer shieldextended position.
 10. Device according to claim 7, wherein said cuttingmeans comprises a penetrating apex cutting means protected by saidpenetrating apex shield, and wherein said penetrating apex cutting meansand said outer cutting means are integrally formed said outer shield ismade as a low profile shield, and said penetrating apex shield and saidouter shield have a longitudinal slot, through which said penetratingapex cutting means and said outer cutting means pass.
 11. Deviceaccording to claim 1, wherein said cutting means comprises a penetratingapex cutting means protected by said penetrating apex shield.
 12. Deviceaccording to claim 1, wherein said portal unit has: a portal housinglocated on the proximal end of said tubular cannula; seals located insaid portal housing for prevention a gas leakage from the body cavity; alocking means for locking said protector means in said extendedposition.